RE: combat submarines
I believe the Robbe U47 is 1/40 scale, I believe. That is hugely too large (out of spec) for 1/144, 1/96, or even 1/72 combat clubs (1/144 being the most common/numerous). So, the answer seems to be no. Sorry.
Doo keep in mind that under most club's rules, you would need to cut holes in the hull and skin with balsa to make it sinkable. There are tons of technical issues with fighting a sub in combat remotely. Even if you can resolve them, there is still the underlying operational issue - If your enemy cannot see your sub, neither can you. This kind of removes som e of the sub's "advantage."
Cheers,
Wreno